Microvast, Inc. launched its non-flammable battery technology for lithium-ion batteries at a press conference event held at the Water Cube in Beijing.
This technology is a breakthrough for the industry, resolving battery safety issues through a multi-level approach from materials to the system level. The new technology takes both active and passive protection measures in order to enhance product safety, including improvements to the battery’s electrolyte, separator and protection system. Over 200 delegates including government officials, industry experts, operators, automotive OEMs and members of the press attended the event.
Wu Yang, CEO of Microvast, Inc., opened his speech with the topic of “Fire”. Although the electric vehicle market experienced a huge upswing last year, especially in China, global automotive giants have not responded to the demand with increased large-scale production and sales. One of the important reasons for this is the unpredictable flammable nature of lithium-ion batteries. The lithium-ion battery has certain risk of random short-circuiting during its production and use, which can cause accidents. Even with a high quality control standard in place (i.e., 2ppm for 18650 cylindrical batteries), in every 100,000 vehicles sold, 1,600 of them would have batteries at risk of bursting into flame.
In 2008 when Microvast started to focus its research on electric vehicle power systems, Microvast established three main objectives: “10-Minute Ultra-Fast Charge”, “Long Battery Life”, and “Non-flammable”. These three points are the foundation of Microvast’s primary business strategy, the Clean City Transit (CCT) plan. Today, with the implementation of the CCT plan, both the “10-Minute Ultra-Fast Charge” and the ”Long Battery Life” technologies have been widely accepted by Microvast’s customers. Microvast’s battery power systems have been installed in more than 10,000 electric buses worldwide in 26 provinces across China and four countries in Europe. After 8 years of intensive research, Micovast has finally revealed its non-flammable technology.
Non-flammable electrolyte that ensures both ultra-fast charge and long battery life
Research has shown that when thermal runaway occurs in a lithium-ion battery, most of its heat is released by electrolytes, which means electrolytes need to be controlled to ensure safety. However, it is a challenge to develop non-flammable electrolytes with ultra-fast charge capability and long life. Thanks to the tremendous efforts by its research team, Microvast has developed an electrolyte that is non-flammable and can be fully charged within 10-15 minutes and with a cycle life of over 10,000 times.
Temperature tolerance separator
A high performance separator is also an important protection measure for lithium-ion batteries. A normal lithium-ion battery separator has a low melting point and will usually shrink around 130°C. The resulting short circuit will lead to thermal runaway of the battery. As a membrane expert with over 30 years of experience, Microvast’s Chief Technology Officer (CTO), Xiang Li, announced the high temperature membrane separator at today’s event. The newly developed separator has a higher melting point compared with commercial ones, which ensures that it does not shrink even at temperatures of up to 300°C. This reduces the possibility of thermal runaway and short circuiting.
STL-System level protection measure
In addition to improvements to the electrolyte and separator, the Smart Thermal Liquid (STL) technology is applied to the battery as a protection system, with the battery module immersed in the liquid. As a preferable material of insulation, flame retardation and thermal conductivity, STL can isolate any thermal runaway points in the case of short circuiting. Meanwhile, by deploying liquid to reduce the temperature of any thermal runaway point, STL can significantly lower the risk of short circuiting. As a passive protection system, STL also balances temperature differences inside the battery and applies outside circulation to control the battery temperature. Furthermore, the STL can detect any battery leakage that may happen in the battery pack.
The non-combustion electrolyte and the temperature tolerance separator are two active protection methods. Combined with STL intelligent thermal control fluid technology, Microvast has achieved its goals of non-combustion, advanced safety and high performance in a battery system. A demonstration of the combustion of different battery cells was performed at the launch event , which displayed the impressive coordination of non-combustion technology and a normal lithium-ion battery.